Lazard’s relationship with the Brazilian backers of 3G Capital, which this week carried out the high profile $4bn acquisition of Burger King, stretches back to 2004 when it advised on the formation of a brewing giant.

The independent investment bank is one of the three advisers to 3G Capital, the New York-based investment firm that is buying the fast food chain from private equity backers Bain Capital, Goldman Sachs' buyout arm and TPG.

Its role in the deal – which has earned it the title of investment bank of the week – shows the importance of relationships in large M&A deals.

Antonio Weiss, who was promoted global head of investment banking at Lazard last year, is understood to be on the team acting for 3G Capital alongside Alexander Hecker in the bank’s New York office.

Weiss was an important figure in the formation of brewer InBev. Data provider mergermarket said at the time that he was involved in the $11bn merger of Belgian Interbrew and Brazil’s Ambev in 2004.

However, Lazard had been advising Interbrew on the deal, having been a long-standing adviser to the Belgian company since 1995.

Weiss then helped Lazard retain its role as one of the advisers to InBev on its $60bn acquisition of Anheuser-Busch, the US brewer of Budweiser in 2008. Lazard subsequently advised Anheuser-Busch InBev on the sale of assets worth a combined €5bn. The sale of InBev assets contributed to Weiss being named as last year’s most prolific M&A banker, according to mergermarket.

Until 3G Capital hit the headlines with the Burger King deal, it had not been well known, besides the fact that it employs Marc Mezvinsky, who married Chelsea Clinton last month.

Its managing partner is co-founder Alex Behring, according to the firm’s website. He works closely with 3G Capital backer, Jorge Paulo Lemann, who is one of Brazil’s richest men. He built up Banco de Investimentos Garantia before selling it to Credit Suisse for $675m, according to Forbes.

3G Capital said it received debt commitment letters from JPMorgan Chase and Barclays Capital to provide the debt financing necessary to close the transaction. BarCap and JP Morgan are also financial advisers alongside Lazard.